148 Scientific Proceedings, Royal Dublin Society. 



material. I named my new burner the " Intensity " burner, and 

 having made many experiments, I found that its illuminating 

 power was 100 per cent, greater than that of its predecessors : 

 practically double that of the most powerful gas light now used 

 in lighthouses. 



You will doubtless consider that this statement is one of much 

 importance, deserving careful investigation. I am glad that by 

 the experiment which I will show you I can prove it to demon- 

 stration, for by means of the 30-foot photometer which I have 

 fixed across the Lecture Theatre you can ascertain the fact for 

 yourselves. At the left-hand end of the photometer I have a gas 

 burner of the kind now used in lighthouses, and at the other end 

 the new burner which, as you see, is somewhat similar in con- 

 struction.^ When the burners were first lighted I did not add to 

 the new burner the improvements to which I have referred, and 

 therefore you have seen that both burners were practically the 

 same, consuming the same quantity of the same kind of gas, and 

 having the same illuminating power ; so far we had equality of 

 light, but when I shall add the means by which the superior light 

 of the new burner is produced an enormous increase of illuminating 

 power will be the result. I may mention, in passing, that it is a 

 singular fact that when this improved burner is at full power there 

 is a slight decrease in its consumption, due, I believe, to the slower 

 flow of the richer gas. [The lecturer having added its improvement 

 to the Intensity burner, and having placed the disc of the photometer 

 at an equal distance from each light, it showed that the side next 

 the new burner was more illuminated than the other, proving that 

 the new burner was the more powerful. As he moved the disc 

 towards the less powerful light each side of the disc did not become 

 equally illuminated until it stood at the figure 4 ; which meant that 

 the new burner was further from the disc in the proportion of one to 

 two, and had therefore four times the illuminating power of the 

 other light. At the lecturer's request, Mr. Moss stepped forward 

 and verified this by inspecting the disc of the photometer. At the 



1 The Lecturer here showed a Lighthouse hurner of the kind used in Irish Light- 

 houses, fixed at one end of the Photometer, and at the other end one of his new 

 " Intensity " burners, but without its improvements. Both lights were the same in 

 illuminating power. 



